212121001 has 4 divisors (see below), whose sum is σ = 213998292. Its totient is φ = 210243712.

The previous prime is 212120983. The next prime is 212121023. The reversal of 212121001 is 100121212.

212121001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45091225 + 167029776 = 6715^2 + 12924^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121001 - 2⁷ = 212120873 is a prime.

It is a super-3 number, since 3×212121001³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212121031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 938476 + ... + 938701.

It is an arithmetic number, because the mean of its divisors is an integer number (53499573).

Almost surely, 2^212121001 is an apocalyptic number.

It is an amenable number.

212121001 is a deficient number, since it is larger than the sum of its proper divisors (1877291).

212121001 is a wasteful number, since it uses less digits than its factorization.

212121001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1877290.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 212121001 is about 14564.3743772261. The cubic root of 212121001 is about 596.3866170489.

Adding to 212121001 its reverse (100121212), we get a palindrome (312242213).

It can be divided in two parts, 21212 and 1001, that multiplied together give a palindrome (21233212).

The spelling of 212121001 in words is "two hundred twelve million, one hundred twenty-one thousand, one".